This invention relates to an adjusting device with an overload slip system.
An adjusting device of the type to which the invention relates is disclosed in U.S. Pat. No. 4,101,206. This prior device comprises a housing; an electric drive motor mounted in said housing; a planetary transmission system adapted to be driven by said motor, said transmission system including a sunwheel coupled to the motor shaft, a set of planet gears each having two different sets of teeth, one set of which meshes with an internally toothed stationary ring, and the other with a drivable drum carrying the power output shaft, said power output shaft having a toothed portion meshing with a toothed portion of an adjusting member. The adjusting device forms part of a mirror adjusting instrument. The adjusting member is movable between two extreme positions defined by stops. When the adjusting member is in contact with one of these stops, the driving motor continues to run, so that, at some position between the driving motor and the adjusting member, slip must occur in the driving system. In this prior construction, slip occurs between the adjusting member and the power output shaft of the driving system, caused by the adjusting member being resilient and being laterally deflected by the teeth on the power output shaft of the driving system. The teeth of the power output shaft can thus continue to rotate without displacing the adjusting member which abuts a stop.
This prior construction functions excellently, but presents problems if it is desired to place the adjusting member in a plurality of pre-programmed positions by means of the driving system. This requires a position indicator, which in this prior construction could only be mounted on the adjusting member proper, because there is no fixed relation between the position of the adjusting member and the angular position occupied by the driving system. Mounting a position indicator on the adjusting member is difficult and complicated, especially also because the adjusting member must be resilient.